Tampering with multipart negotiable instruments, such as checks, drafts, and tickets, such as airline tickets, by altering the amounts or destinations, or other information causes great monetary losses to the enterprises issuing them. Although various proposals have been made to alleviate this problem, they have not been entirely successful.
Substantially all of the efforts in preparing tamper-resisting negotiable instruments have been directed either toward tamper-resisting inks and indicia printed with them or to the construction of the web that comprises the instrument itself, rather than to providing an additional web that can be used to verify the information upon the instrument. Various attempts to solve the post-issuance alteration problem in negotiable instruments and credit card-type applications can be found in U.S. Pat. Nos. 4,143,891, 4,051,295 and 4,092,449.
None of the above art teaches or suggests that a tamper-resisting negotiable instrument can be prepared that contains a separate, verifying web as is described herein.
In addition, tickets such as airline tickets are typically coated on their back sides with a colorant such as a dye or pigment dispersed in a hydrophobic medium such as an oil plasticized carnauba wax. That coating serves to transfer an image inscribed on the upper ticket blank to the ticket blank therebelow.
Such materials, while effective for transferring images, suffer from at least two drawbacks. First, the transferred image may readily be removed by light rubbing with an organic solvent or by placing an adhesive tape over the transferred image followed by removing the tape and adhered image. Second, those image transferring coatings have been found to cause respiratory and other problems among personnel who make the ticket blanks, and also provide a fine mist of colored material in the work environment.